Special consideration

I just had a chemistry A-level exam and I had a really bad panic attack during this exam, I tried to calm down but I started hyperventilating so I had to step out of the exam hall, they took me to the medical and I got sent home since it was a bad condition, I did not complete my exam paper and I am not confident in the questions I did since I wasn't in the right mind give it my100%. I applied for special consideration like my teacher told me to.
But I don't know how it's going to work, am I going to lose all my marks for the paper?
Will they let me re-sit my exam?
Will they look at my mocks? (I did really bad in my mocks)
I'm really scared since this is my real A-level paper and I will be disadvantaged by this situation.
Thankyou in advance